/* -----------------------------------------------------------------------
 * ascii.c
 *	 The openGauss routine for string to ascii conversion.
 *
 *	 Portions Copyright (c) 1999-2012, PostgreSQL Global Development Group
 *
 * IDENTIFICATION
 *	  src/backend/utils/adt/ascii.c
 *
 * -----------------------------------------------------------------------
 */
#include "postgres.h"
#include "knl/knl_variable.h"

#include "mb/pg_wchar.h"
#include "utils/ascii.h"

static void pg_to_ascii(unsigned char* src, unsigned char* src_end, unsigned char* dest, int enc);
static text* encode_to_ascii(text* data, int enc);

/* ----------
 * to_ascii
 * ----------
 */
static void pg_to_ascii(unsigned char* src, unsigned char* src_end, unsigned char* dest, int enc)
{
    unsigned char* x = NULL;
    const unsigned char* ascii = NULL;
    int range;

    /*
     * relevant start for an encoding
     */
#define RANGE_128 128
#define RANGE_160 160

    if (enc == PG_LATIN1) {
        /*
         * ISO-8859-1 <range: 160 -- 255>
         */
        ascii = (const unsigned char*)"  cL Y  \"Ca  -R     'u .,      ?AAAAAAACEEEEIIII "
                                      "NOOOOOxOUUUUYTBaaaaaaaceeeeiiii nooooo/ouuuuyty";
        range = RANGE_160;
    } else if (enc == PG_LATIN2) {
        /*
         * ISO-8859-2 <range: 160 -- 255>
         */
        ascii = (const unsigned char*)" A L LS \"SSTZ-ZZ a,l'ls "
                                      ",sstz\"zzRAAAALCCCEEEEIIDDNNOOOOxRUUUUYTBraaaalccceeeeiiddnnoooo/ruuuuyt.";
        range = RANGE_160;
    } else if (enc == PG_LATIN9) {
        /*
         * ISO-8859-15 <range: 160 -- 255>
         */
        ascii = (const unsigned char*)"  cL YS sCa  -R     Zu .z   EeY?AAAAAAACEEEEIIII "
                                      "NOOOOOxOUUUUYTBaaaaaaaceeeeiiii nooooo/ouuuuyty";
        range = RANGE_160;
    } else if (enc == PG_WIN1250) {
        /*
         * Window CP1250 <range: 128 -- 255>
         */
        ascii = (const unsigned char*)"  ' \"    %S<STZZ `'\"\".--  s>stzz   L A  \"CS  -RZ  ,l'u .,as "
                                      "L\"lzRAAAALCCCEEEEIIDDNNOOOOxRUUUUYTBraaaalccceeeeiiddnnoooo/ruuuuyt ";
        range = RANGE_128;
    } else {
        ereport(ERROR,
            (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                errmsg("encoding conversion from %s to ASCII not supported", pg_encoding_to_char(enc))));
        return; /* keep compiler quiet */
    }

    /*
     * Encode
     */
    for (x = src; x < src_end; x++) {
        if (*x < 128)
            *dest++ = *x;
        else if (*x < range)
            *dest++ = ' '; /* bogus 128 to 'range' */
        else
            *dest++ = ascii[*x - range];
    }
}

/* ----------
 * encode text
 *
 * The text datum is overwritten in-place, therefore this coding method
 * cannot support conversions that change the string length!
 * ----------
 */
static text* encode_to_ascii(text* data, int enc)
{
    pg_to_ascii((unsigned char*)VARDATA(data),  /* src */
        (unsigned char*)(data) + VARSIZE(data), /* src end */
        (unsigned char*)VARDATA(data),          /* dest */
        enc);                                   /* encoding */

    return data;
}

/* ----------
 * convert to ASCII - enc is set as 'name' arg.
 * ----------
 */
Datum to_ascii_encname(PG_FUNCTION_ARGS)
{
    text* data = PG_GETARG_TEXT_P_COPY(0);
    char* encname = NameStr(*PG_GETARG_NAME(1));
    int enc = pg_char_to_encoding(encname);

    if (enc < 0)
        ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("%s is not a valid encoding name", encname)));

    PG_RETURN_TEXT_P(encode_to_ascii(data, enc));
}

/* ----------
 * convert to ASCII - enc is set as int4
 * ----------
 */
Datum to_ascii_enc(PG_FUNCTION_ARGS)
{
    text* data = PG_GETARG_TEXT_P_COPY(0);
    int enc = PG_GETARG_INT32(1);

    if (!PG_VALID_ENCODING(enc))
        ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("%d is not a valid encoding code", enc)));

    PG_RETURN_TEXT_P(encode_to_ascii(data, enc));
}

/* ----------
 * convert to ASCII - current enc is DatabaseEncoding
 * ----------
 */
Datum to_ascii_default(PG_FUNCTION_ARGS)
{
    text* data = PG_GETARG_TEXT_P_COPY(0);
    int enc = GetDatabaseEncoding();

    PG_RETURN_TEXT_P(encode_to_ascii(data, enc));
}

/* ----------
 * Copy a string in an arbitrary backend-safe encoding, converting it to a
 * valid ASCII string by replacing non-ASCII bytes with '?'.  Otherwise the
 * behavior is identical to strlcpy(), except that we don't bother with a
 * return value.
 *
 * This must not trigger ereport(ERROR), as it is called in postmaster.
 * ----------
 */
void ascii_safe_strlcpy(char* dest, const char* src, size_t destsiz)
{
    if (destsiz == 0) /* corner case: no room for trailing nul */
        return;

    while (--destsiz > 0) {
        /* use unsigned char here to avoid compiler warning */
        unsigned char ch = *src++;

        if (ch == '\0')
            break;
        /* Keep printable ASCII characters */
        if (32 <= ch && ch <= 127)
            *dest = ch;
        /* White-space is also OK */
        else if (ch == '\n' || ch == '\r' || ch == '\t')
            *dest = ch;
        /* Everything else is replaced with '?' */
        else
            *dest = '?';
        dest++;
    }

    *dest = '\0';
}
